<template>

  <div class="app-container">

    <h2 style="text-align: center;">发布新课程</h2>

    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息"/>
      <el-step title="创建课程大纲"/>
      <el-step title="提交审核"/>
    </el-steps>

    <el-form label-width="120px">

      <el-form-item label="课程标题">
        <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
      </el-form-item>

      <!-- 所属分类 TODO -->
      <el-form-item label="课程类别">
        <el-select
          v-model="courseInfo.subjectParentId"
          value-key="index"
          placeholder="一级分类"
          @change="changeTwoSubject">
          <el-option
            v-for="(subject, index) in subjectOneList"
            :key="index"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
        <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
          <el-option
            v-for="(subject, index) in subjectTwoList"
            :key="index"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
      </el-form-item>

      <!-- 课程讲师-->
      <el-form-item label="课程讲师">
        <el-select
          v-model="courseInfo.teacherId"
          placeholder="请选择">
          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"/>
        </el-select>
      </el-form-item>

      <el-form-item label="总课时">
        <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
      </el-form-item>

      <!-- 课程简介  -->
      <el-form-item label="课程简介">
        <tinymce :height="300" v-model="courseInfo.description"/>
      </el-form-item>

      <!-- 课程封面 -->
      <el-form-item label="课程封面">

        <el-upload
          :show-file-list="false"
          :on-success="handleAvatarSuccess"
          :before-upload="beforeAvatarUpload"
          :action="BASE_API+'/oss/fileOss/upload'"
          class="avatar-uploader">
          <img :src="courseInfo.cover" width="400" height="400">
        </el-upload>

      </el-form-item>

      <el-form-item label="课程价格">
        <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
      </el-form-item>
    </el-form>

    <el-form label-width="120px">

      <el-form-item>
        <el-button :disabled="saveBtnDisabled" type="primary" @click="next">保存并下一步</el-button>
      </el-form-item>
    </el-form>
  </div>
</template>
<script>
import courseApi from '@/api/edu/course'
import teacherApi from '@/api/edu/teacher'
import subjectApi from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce'
export default {
  components: { Tinymce },
  data() {
    return {
      saveBtnDisabled: false, // 保存按钮是否禁用
      courseInfo: {
        title: '',
        subjectId: '',
        teacherId: '',
        subjectParentId: '',
        lessonNum: 0,
        description: '',
        cover: '/static/reba.jpg',
        price: 0
      },
      teacherList: [],
      subjectOneList: [],
      subjectTwoList: [],
      BASE_API: process.env.BASE_API,
      courseId: ''
    }
  },

  created() {
    this.getAllTeachers()
    this.getOneSubjectList()
    if (this.$route.params && this.$route.params.id) {
      this.courseId = this.$route.params.id
      this.getCourseInfo(this.courseId)
      subjectApi.getAllSubject().then(res => {
        this.subjectOneList = res.data.tree
        this.subjectOneList.forEach(subject => {
          if (subject.id === this.courseInfo.subjectParentId) {
            this.subjectTwoList = subject.children
          }
        })
      })
    }
  },

  methods: {
    handleAvatarSuccess(res) {
      this.courseInfo.cover = res.data.url
    },
    beforeAvatarUpload(file) {
      const isJPG = file.type === 'image/jpeg'
      const isLt2M = file.size / 1024 / 1024 < 2

      if (!isJPG) {
        this.$message.error('上传头像图片只能是 JPG 格式!')
      }
      if (!isLt2M) {
        this.$message.error('上传头像图片大小不能超过 2MB!')
      }
      return isJPG && isLt2M
    },

    next() {
      if (this.courseId) {
        courseApi.updateCourseInfo(this.courseInfo).then(res => {
          this.$message({
            type: 'success',
            message: '保存成功!'
          })
          this.$router.push({ path: '/course/chapter/' + this.courseId })
        })
      } else {
        courseApi.addCourseInfo(this.courseInfo).then(res => {
          this.$message({
            type: 'success',
            message: '添加成功!'
          })
          this.$router.push({ path: '/course/chapter/' + res.data.id })
        }).catch(error => {
          console.log(error)
        })
      }
    },

    // 讲师列表
    async getAllTeachers() {
      teacherApi.getAllTeachers().then(res => {
        this.teacherList = res.data.data
      })
    },

    // 查询一级课程类型
    getOneSubjectList() {
      subjectApi.getAllSubject().then(res => {
        this.subjectOneList = res.data.tree
      })
    },

    // 监听一级列表变动
    changeTwoSubject(value) {
      this.courseInfo.subjectId = ''
      this.subjectOneList.forEach(subject => {
        if (subject.id === value) {
          this.subjectTwoList = subject.children
        }
      })
    },

    // 根据id查询课程信息
    getCourseInfo(courseId) {
      courseApi.getCourseInfo(courseId).then(res => {
        this.courseInfo = res.data.courseInfo
      })
    }
  }
}
</script>
<style scope>
.tinymce-container {
  line-height: 29px;
}
</style>
